Rolling mill module

ABSTRACT

A rolling mill module for a rolling mill for rolling a billet is disclosed. The rolling mill module has a frame, a first pair of rolls journalled in the frame, and a second pair of rolls journalled in the frame and spaced a predetermined distance from the first pair of rolls so that the temperature drop in the billet between the first pair of rolls and the second pair of rolls is minimized. The rolling mill module is adapted to be readily removed from the rolling mill for repairs or replacement.

United StatesPatent [1 1 Jones et al.

ROLLING MlLL MODULE Inventors: Donald A. Jones, Bethel Park;

Howard S. Orr, Upper St. Clair Township, Allegheny County; Francis K. Qualey, Churchill, all of Assignee: United States Steel Corporation Filed: Mar. 20, 1972 Appl. No.: 235,992

US. Cl 72/234, 72/238, 72/245 Int. Cl .Q. B2lb 13/08 Field of Search 164/76, 270; 72/234, 238, 239,

References Cited UNITED STATES PATENTS 4/1971 Eibe, 72/227 [451 Jan. 22,1974

3,621,694 11/1971 Greenberger ..72/24TX 3,677,056

7/1972 Properze 72/227 Primary Examiner-Milton S. Mehr Attorney, Agent, or Firm-Robert J. Leek, Jr.

[5 7] ABSTRACT 23 Claims, 6 Drawing Figures SHEU 1 BF 4 FIG. 5.

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Wm mm mm ROLLING MILL MODULE BACKGROUND OF THE INVENTION Heretofore, in the continuous casting process, a definite. product size must be established so that the semifinished cast productwill be adaptable to the required finishing processes. The semi-finished cast product can be finished by one of two means: (1) by reheating the cast product and finishing it in a conventional rolling mill; or (2) by rolling the cast product directly from the casting machine. However, if the semi-finished cast product is to be rolled directly from the casting machine, the temperature of the cast product is very critical due to the slow casting speed.

In conventional rolling mills, a specific product size is moved into a reheat furnace to bring the product up to the desired temperature for rolling. This product, semi-finished, is then rolled through the rolling mill at as high a speed as possible to keep the temperature as high and as uniform as possible thereby insuring good product quality. However, when a rolling machine is used in conjunction with a continuous casting machine, the speed at which the semi-finished cast product is rolled is dependent upon the casting speed of the continuous casting machine. This casting speed is very slow (i.e;, about 6-18 fpm) when compared to the rolling speed of conventional rolling mills. Since the casting speed is slow, the temperature of the cast product will drop and make rolling of the product difficult. Therefore, the rolling mills must be kept as close to the casting machine as possible. Also, for smaller cast sections such as billets,-the temperature of the cast product reduces significantly between passes of the conventional rolling mill stands making rolling of the'product difficult. Such conventional rolling mill stands are spaced about 6 feet to 10 feet apart.

We are aware of the following prior art:

US. Pat. No. Issued Inventor Class 3,280,6l l0l25l66 Qualey 72/245 3,358,358 l2ll9/67 Jenks et al. 29/528' 3,628,594 l2/2l/7l v Reinfeld et al. l64/270 OBJECTS OF THE INVENTION It is the general object of this invention to avoid and overcome the foregoing and other difficulties of and objections to prior 'art practices by the provision of an improved rolling mill module for a continuous casting a line, which module:

c. has its rolls adapted to operate dry by the utiliza- 7 tion of a hot die steel for a roll collar and high alloy steel for the roll body; r

d. is equipped to be cooled by air, steam, water vapor, or the like;

e. has its individual roll collars and roll bodies held together by toleranced fits rather than by mechanical the like, and automatically returning the rolls to the normal open position;

g. has its vertical rolls removable in a vertical plane and is then tilted about to remove the horizontal rolls in the vertical plane; and

h. uses differential pressure roll spacing means to space a pair of rolls in the rolling position.

BRIEF SUMMARY OF THE INVENTION The aforesaid objects of this invention and other objects which will become apparent as the description proceeds are achieved by providing an improved rolling mill module for a rolling mill for rolling a billet.

The rolling mill module has a frame, a first pair of rolls joumaled in the frame and a second pair of rolls also joumaled in the frame and spaced a predetermined distance from the first pair of rolls so that the temperature drop in the billet between the first pair of rolls and the second pair of rolls is minimized. The rolling mill module is adapted to be readily removed from the rolling mill for repairs or replacement.

BRIEF. DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS For a better understanding of this invention, reference should be had to the accompanying drawings, wherein like numerals of reference indicate similar parts through the several views and wherein:

FIG. 1 is a diagrammatic side elevational view of a multistrand (i.e., four strand) continuous casting line showing diagrammatically the preheat means, the scale breaker and two of the rolling mill modules of the present invention associated with line No. l of the plural line continuous casting apparatus;

FIG. 2 is a diagrammatic plan view of the rolling mill modules, preheat means and scale breakers associated with the four strands of the continuous casting apparatus;

FIG. 3 is a horizontal sectional view of a pair of vertical rolls of the module taken along the line 33 of FIG. 2 in the direction of the arrows;

FIG. 4 is a diagrammatic plan view, partially in section, of the pressure control means associated with the pair of vertical rolls shown in FIG. 3; and

FIGS. 5 and 6 are diagrammatic plan views respectively of rolling mill modules having two pairs of vertical rolls and two pairs of horizontal rolls respectively.

Although the principles of this invention are broadly applicable to rolling mill modules, this invention is particularly adapted for use in conjunction with a continuous casting apparatus, and hence it has been so illustrated and will be so described.

DETAILED DESCRIPTION 18 (FIG; 1), pinch rolls 20 (FIG. 1), a fulcrum roll 22 I and pusher roll 24 (FIG. 1 and then individually onto a conveyor (not shown in FIG. 1) for delivery through in succession, induction type preheat means 26 (FIGS.

1,2) a scale breaker 28 (FIGS. 1,2), and, for example, a pair of improved rolling mill modules 30a,30b (FIGS. 1,2). It will be understood from a consideration of FIG. 2 that the strands 14, 14 14 14" are supported on conveyors 32, 32 32 32 (FIG. 2) with each conveyor 32', etc., comprise a plurality of rolls 34 and guides 36.

Rolling Mill Modules 30a,30b

As shown particularly in FIGS. 2 and 3, each rolling mill module 30a,30b has a frame 38 (FIGS. 1-6). A first pair of rolls R, (FIGS. 1,2) of the horizontal roll type are journaled in the frame 38. A second pair of rolls R (FIGS. 1,2) of the vertical type rolls are journaled in the frame 38 and spaced a predetermined distance D (FIG. 2) from the first pair of rolls R, so that the temperature drop in the strand 14, etc. between the first pair of rolls R and the second pair of rolls R is minimized. The rolling mill module 30a or 30b is adapted to be readily removed from the rolling mill by the provision of engaging means, such as lugs 40 (FIGS. 1,2,S,6) or the like on the frame 38, which lugs 40 are adapted to be engaged by a removal means, such as a crane or the like, not shown, so that the rolling mill module 30a,30b may be readily removed from the continuous casting apparatus 10.

In addition to the first pair of horizontal rolls R, and the second pair of vertical rolls R the rolling mill module 30a has a third pair of horizontal rolls R, (FIGS. 1,2) and a fourth pair of vertical rolls R The adjacent rolling mill module 30b has a fifth pair of horizontal rolls R,,,, a sixth pair of vertical rolls R a seventh pair of horizontal rolls R and an eighth pair of vertical rolls Ray.

Operation of the Rolling Mill Modules 30a,30B

A strand, such as the first strand 14, having a square cross section of about 7- /1 inches is fed into the first and second pair of rolls R, and R (FIGS. 1,2) where such strand I4 is reduced in square cross section to about 6-% inches. Passage of the strand 14' through the third and fourth sets of rolls R and R further reduce the square cross section of the strand 14 to about 6 inches. Such strand [4 is further reduced in roll pairs R and R to about a square cross section of 5 inches and finally reduced in roll pairs R and R to a final square cross section of about 4 inches.

Since each of the eight pairs of rolls R R R R R R R and R basically have the same construction and operation, the individual pair of rolls will be described with respect to FIG. 3 and the vertical pair of rolls R Vertical Roll Pair R As shown in FIG. 3, the frame 38 (FIGS. 1-6) of the rolling mill module 30a is provided with partitions 42 (FIGS. 3,4) between adjacent pairs of rolls, such as the horizontal rolls R, to the left of the vertical roll pair R and the horizontal roll pair R to the right of the vertical roll pair R as viewed in FIG. 1.

First Roll 44 The vertical roll pair R has a first roll 44 (FIGS. 3,4) having a first roll sleeve 46 (FIG. 3) mounted on a first roll shaft 48 (FIG. 3) by means of a tolerance fit between the roll sleeve 46 and the roll shaft 48. The first roll shaft 48 is journaled in suitable bushings (not shown) in the frame 38 and is rotated by means of flexible drive shaft similar to the device shaft 50 (FIGS. 3,4). This first roll 44 is mounted in a first roll mounting means, such as a roll chuck 52 (FIGS. 3,4) or the like, suitably of split half construction secured together by bolts 54 (FIG. 3). The means utilized to move the first roll 44 from an open position (not shown in FIG. 3) to the rolling position shown in FIG. 3 is a first fluid operating means, such as a first fluid cylinder 56 (FIGS. 3,4) having an operating piston 58 (FIGS. 3,4) engageable with the roll chuck 52 through a first shim means 60 (FIG. 3) secured to the roll chuck 52 by means of bolts 62 (FIG. 3). The roll chuck 52 is reciprocable between the open position (not shown in FIG. 3) and the rolling position shown in FIG. 3 on guides or liners 64 (FIG. 3) carried either by the roll chuck S2 or the partition 42 of the frame 38.

Second Roll 66 The second roll 66 (FIGS. 3,4) of the vertical roll pair R is similarly constructed and is actuated by a second fluid operating means, such as the second fluid cylinder 68 (FIGS. 3,4). It will be understood that the first fluid cylinder 56 is adapted through its larger diameter piston 58 than the piston 70 (FIGS. 3,4) of the second fluid cylinder 68 to provide a greater fluid pressure on the first roll 44 than the second fluid cylinder 68 applies to the second roll 66 so that spacing means, such as a second shim means 72 (FIG. 3) carried by either of the roll chucks 52 limits the operating stroke of the second fluid cylinder 68 when the first fluid cylinder 56 reaches the end of its stroke, thereby providing the predetermined rolling spacing d (FIG. 3) between the first roll 44 and the second roll 66, as the first roll 44 and the second roll 66 move from the open position (not shown in FIG. 3) to the rolling position (FIG. 3).

It will be understood from a consideration of FIG. 3 that the strand 14 moves (in the direction of the horizontal arrow in FIG. 3) along the centerline AA (FIG. 3) on the conveyor means 32 (FIG. 2) or the centerline of the adjacent pairs of rolls R and R (FIG. 3) through a tapered opening 74 in the left hand partition 42 (as viewed in FIG. 3) of the frame 38; through the rolls 44 and 66 in the rolling position shown in FIG. 3; and through an outlet 76 in the other right hand partition 42, as viewed in FIG. 3, adjacent the exit side of the pair of vertical rolls Rzy.

Since the first fluid cylinder 56 and the second fluid cylinder 68 are of the single acting type as shown in FIG. 4, thp pair of vertical rolls R is provided with a roll retracting means 78 (FIG. 3).

Roll Retracting Means 78 This roll retracting means 78 (FIG. 3) is associated with one of the rolls 44,66 of the first roll 44 and the second roll 66 (in this case, the second roll 66) and is adapted to engage the other roll (in this case the first roll 44 of the first roll 44 and the second roll 66) so that the fluid pressure is removed (as hereinafter explained) from the first fluid cylinder 56 and the second fluid cylinder 68, the roll retracting means 78 returns the first roll 44 and the second roll 66 to the open position (not shown in FIG. 3).

The roll retracting means 78 has a pair of fluid cylinders 80a and 80b (FIG. 3) carried by the roll chuck 52 associated with the second roll 66. The cylinders 80a,80b are secured to the roll chuck 52 associated with the second roll 66 by means of bolts 82 (FIG. 3). The operating pistons 84a,84b of the fluid cylinders 80a,80b engage the second shim means 72 carried by the roll chuck 52 associated with the first roll 44 and move the first roll 44 and second roll 66 from the rolling position shown in FIG. 3 to the open position (not shown in FIG. 3). The fluid enters the single acting fluid cylinders 80a,80b through inlets 86a,86b (FIG. 3).

In addition, each rolling mill module 30a,30b is provided with a pressure release means 88 (FIG. 4) which pressure release means 88 is operable when the pressure between the first roll 44 and the second roll 66 (when such rolls 44 and 66 are in the rolling position of FIG. 3) exceeds a predetermined pressure, such as about 2,700 psi, to release such fluid pressure on the first fluid cylinder 56 and the second fluid cylinder 68 thereby preventing damage to the first roll 44 and the second roll 66. This excessive pressure may be caused by cast cold head ends, cold tail ends, or the like. The pressure release means 88 automatically releases the first roll 44 and the second roll 66 from the rolling position shown in FIG. 3.

Pressure Release Means 88 As shown in FIG. 4, the pressure release means 88 has a normally closed pressure switch 90 (FIG. 4) of the type manufactured by Allen Bradley Company, Milwaukee, Wis., connected by means of a branch line 92 to the fluid supply line 94 (FIG. 4). The fluid supply line 94 extends from the hydraulic fluid supply identified by the arrow and the legend FROM HYDRAULIC FLUID SUPPLY through a four-way, two position hydraulic directional valve 96 (FIG. 4) to the first fluid cylinder 56 and the second fluid cylinder 68. The hydraulic directional valve 96 is normally held in the release position shown in FIG. 4 by means of biasing means, such as a spring 98 (FIG. 4) or the like, and the normally closed pressure switch 90 is similarly held in the normally closed position by means of a similar spring 100 (FIG. 4) or the like. The hydraulic four-way,

two position valve 96 is of the type manufactured by Republic Manufacturing Company, Cleveland, Ohio. The means utilized to move the pressure relief valve 96 from the relief position (shown in FIG. 4) to the fluid operating position (not shown in FIG. 4) is a solenoid 102 (FIG. 4). Such solenoid 102 t and the pressure switch 90 are connected to and operable by an electrical operating circuit 104 (FIG. 4).

This circuit 104 has lines LI,L2 extending from a suitable voltage supply, indicated by the legend AC SUPPLY, through a normally open holding contact R of a relay 108 to one side of the solenoid I02 and to the other side of such solenoid 102 respectively. A parallel line L3 connects the line Ll through the pressure switch 90, the relay 108, a manually operated, normally open, starting switch 110, and a manually operated, normally closed stop switch 112 to the line L2 thereby connecting the pressure switch 90, the relay 108 and the switches I10 and 112 in parallel with the solenoid 102. As shown in FIG. 4, a normally open holding contact R, of the relay 108 is disposed in parallel about the normally open manually operating starting switch 110, which switch 110 and the stop switch 112 are disposed in the pulpit (not shown) associated with the rolling mill (not shown).

In order to move the first roll 44 and the second roll 66 from the normally open position (not shown in FIGS. 3,4) to the rolling position shown in FIGS. 3 and 4, the normally open manually operated starting switch 110 is closed, thereby energizing the relay I08 and closing both the normally open hold contact R, and the normally open contact R of such relay I08 with attendant energization of the solenoid I02 so that the hydraulic directional valve 96 is moved downwardly from the position shown in FIG. 4 to the fluid applying position (not shown) where fluid pressure is applied directly through line 94 to the first fluid cylinder 56 and the second fluid cylinder 68 to move the rolls 44 and 66 to the closed or rolling position shown in FIG. 4.

If the rolls 44 and 66 should engage a cast cold head end, cold tail end or the like and the pressure between such rolls 44,66 exceeds about 2700 psi, the pressure switch 90 moves to the open position, thereby deenergizing the relay 108 with attendant opening of the now closed holding contacts R, and R of such relay 108 and the resultant deenergization of the solenoid 102 and the return of the hydraulic directional valve 96 from the fluid operating position (not shown in FIG. 4) to the pressure relief position shown in FIG. 4 with the help of the biasing spring 98.

If, for some unknown emergency, it is desired to deenergize the solenoid 102, the manually operated, normally closed stop switch 112 located in the pulpit (not shown) in the rolling mill (not shown) may be opened, thereby deenergizing the electrical operating circuit 104 as above described.

For the purpose of rotating the first roll 44 and the second roll 66, a drive means 114 is provided.

It will be appreciated by those skilled in the art that whpn the hydraulic pressure is removed from the pistons 58 and associated with the first roll 44 and the second roll 66 by the pressure release means 88, that the roll retracting means 78 (FIG. 3) automatically returns the first roll 44 and the second roll 66 from the rolling position shown in FIGS. 3 and 4 to the open position (not shown).

Drive Means I14 As shown particularly in FIG. 2, the drive means 114 has a motor 116 connected through a gear reducer 118 to the flexible shaft 50 shown in FIGS. 2 and 3. Each individual drive means I14 is operable to rotate the flexible shaft 50 and the attached individual pairs of rolls R R etc. in the direction of the arrows shown in FIGS. 2 and 3.

It will be understood from the above description that the predetermined distance D (FIG. 2) between the roll centers of the first pair of rolls R, and the second pair of rolls R ,'for example, should desirably be less than the maximum roll diameter of the first pair of rolls R, and the second pair of rolls R plus about 4 inches, thereby minimizing the spacing between adjacent pairs of the rolls, such as the pairs R R etc. from about 18 to about 20 inches.

ALTERNATIVE EMBODIMENTS It will be understood by those skilled in the art that alternatively as shown in FIG. 5, the rolling mill module 30" may have mounted within the frame 38 a first pair R of the vertical rolls and a second pair R of vertical rolls.

Similarly, as shown in FIG. 6, a rolling mill module 30 may have a first set R, of the horizontal rolls and a second set R of horizontal rolls.

It will also be appreciated by those skilled in the art that alternatively, the first pair R, of horizontal rolls and the second pair R of the vertical rolls shown in FIG. 2 may be rotated 90 from the position shown in FIG. 2 so that such pairs R and R of rolls may be utilized to reduce a billet having a diamond cross section rather than square cross section, shown in FIG. 2.

SUMMARY OF THE ACHIEVEMENTS OF THE OBJECTS OF THE INVENTION It will be recognized by those skilled in the art that the objects of this invention have been achieved by providing improved rolling mill modules 30a,30b (FIGS. 14), 30 (FIG. 6), and 30 (FIG. 6) for a rolling mill (FIG. 1) for rolling a strand or billet 14, 14 14", 14 The improved rolling mill modules 30a, 30b (FIGS. 1-4) etc. give a minimum roll spacing D (FIG. 2) of about 18 inches to about 20 inches between the centerline of adjacent pairs R, and R for example, of the rolls, so that the temperature drop can be kept at a minimum when rolling a strand I4, 14 etc., or billet; permit the removal of the rolling mill module a,30b (FIGS. 1-4), etc. in one lift for roll changing; have their pairs R R etc. of rolls adapted to operate dry by utilization of a hot die steel for a roll collar or sleeve 46 and a high alloy steel for the roll body or shaft 48 (FIG. 2); are also adapted to be cooled by air, steam, water vapor, or the like, have their individual roll collars or roll sleeves 46 and roll bodies or shafts 48 (FIG. 2) held together by tolerance fits; have built-in pressure release means 88 for limiting the roll pressure to about 250,000 pounds or about 2,700 psi, thereby preventing damage to the pairs or rolls R,,,, R etc. from cast cold head ends, cast cold tail ends, or the like, and for automatically retaining the pairs of rolls R,,,, R in the open position (FIGS. 3,4); have their vertical pairs in rolls Rzy, R etc. removable in a vertical plane from the frame 38 of the improved rolling mill modules 30a, 3%., etc., and are then tiltable about 90 to remove the pairs R,,,, R etc. of rolls in the vertical plane; and utilize differential pressure roll spacing means, such as the larger first fluid cylinder 56 and the smaller second fluid cylinder 68 to space the pairs R R etc., of rolls in the rolling position (FIGS.3,4).

While in accordance with the patent statutes, preferred and alternative embodiments of this invention have been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

We claim:

1. A rolling mill module for a rolling mill for rolling a billet, said module having:

a. a frame;

b. a first pair of rolls journalled in said frame;

c. a second pair of rolls journalled in said frame and spaced a predetermined distance from said first pair of rolls when the first pair of rolls and the second pair of rolls are in the rolling position so that the temperature drop in said billet between said first pair of rolls and said second pair of rolls is minimized;

d. said module being adapted to be readily removed from said rolling mill; and

e. wherein one pair of rolls of said first pair of rolls and said second pair of rolls has:

I. a first roll journalled in said frame;

2. a second roll journalled in said frame and disposed adjacent said first roll;

3. a first fluid operating means connected to one roll of said first roll and said second roll; 4. a second fluid operating means connected to the other roll of said first roll and said second roll; 5. said first fluid operating means being adapted to provide greater fluid pressure on said one roll than said second fluid operating means applies to said other roll; and

6. spacing means carried by one roll of said first roll and said second roll so that when said first fluid operating means reaches the end of its stroke, said spacing means limits the operating stroke of said second fluid operating means thereby providing a predetermined rolling spacing between said first roll and said second roll as said first roll and said second roll move from an open position to a rolling position.

2. The rolling mill module recited in claim 1 and having:

a. a first roll mounting means for mounting said first roll and adapted to be engaged by said first fluid operating means; and

b. a second roll mounting means for mounting said second roll and adapted to be engaged by said second fluid mounting means.

3. The rolling mill module recited in claim 1 and having roll retracting means associated with one roll of said first roll and said second roll and adapted to engage the other roll of said first roll and said second roll so that when the fluid pressure is removed from said first fluid operating means and said second fluid operating means, said roll retracting means returns said first roll and said second roll to the open position.

4. The rolling mill module recited in claim I and having a pressure release means associated with said first fluid operating means and said second fluid operating means, said pressure release means being operable when the pressure between said first roll and said second roll exceeds a predetermined pressure to release the fluid pressure on said first fluid operating means and said second fluid operating means thereby preventing damage to said first roll and said second roll from east cold head ends, cold tail ends or the like and automatically releasing said first roll and said second roll from said rolling position.

5. The rolling mill module recited in claim 3 and having a pressure release means associated with said first fluid operating means and said second fluid operating means, said pressure release means being operable when the pressure between said first roll and said second roll exceeds a predetermined pressure to release the fluid pressure on said first fluid operating means and said second fluid operating means thereby preventing damage to said first roll and said second roll from east cold head ends, cold tail ends or the like and automatically permitting said roll retracting means to return said first roll and said second roll from said rolling position to said open position.

6. The rolling mill module recited in claim 1 wherein said first pair of rolls are horizontal rolls.

7. The rolling mill module recited in claim 1 wherein said first pair of rolls are vertical rolls.

8. The rolling mill module recited in claim 1 wherein said first pair of rolls are angularly disposed with respect to a vertical axis of said module.

9. The rolling mill module recited in claim I wherein said second pair of rolls are horizontal rolls.

10. The rolling mill module recited in claim 1 wherein said second pair of rolls are vertical rolls.

11. The rolling mill module recited in claim 1 wherein said second pair of rolls are angularly disposed with respect to said module.

12. The rolling mill module recited in claim 1 and. having:

a. a first drive means connected to said first pair of rolls for rotating said first pair of rolls; and

b. a second drive means connected to said second pair of rolls for rotating said second pair of rolls.

13. The rolling mill module recited in claim 1 wherein said predetermined distance between the roll centers of said first pair of rolls and said second pair of rolls is less than the maximum roll diameter of said first pair of rolls and said second pair of rolls plus about four inches.

14. The rolling mill module recited in claim 1 and having engaging means adapted to be engaged by a removal means so that said module can be readily removed from said rolling mill.

15. A rolling mill module for a rolling mill for rolling a billet, said module having:

a. a frame;

b. a first pair of rolls journalled in said frame;

c. a second pair of rolls journalled in said frame and spaced a predetermined distance from said first pair of rolls when the first pair of rolls and the second pair of rolls are in the rolling position so that the temperature drop in said billet between said first pair of rolls and said second pair of rolls is minimized; and

d. wherein said predetermined distance between the roll centers of said first pair of rolls and said second pair of rolls is less than the maximum roll diameter of said first pair of rolls and said second pair of rolls plus about four inches.

16. The rolling mill module recited in claim 15 wherein said first pair of rolls are horizontal rolls.

17. The rolling mill module recited in claim 15 wherein said first pair of rolls are vertical rolls.

18. The rolling mill module recited in claim 15 wherein said first pair of rolls are angularly disposed with respect to a vertical axis of said module.

19. The rolling mill module recited in claim 15 wherein said second pair of rolls are horizontal rolls.

20. The rolling mill module recited in claim 15 wherein said second pair of rolls are vertical rolls.

21. The rolling mill module recited in claim 15 wherein said second pair of rolls are angularly disposed with respect to said module.

22. The rolling mill module recited in claim 15 and having:

a. a first drive means connected to said first pair of rolls for rotating said first pair of rolls; and

b. a second drive means connected to said second pair of rolls for rotating said second pair of rolls.

23. The rolling mill module recited in claim 15 and having engaging means adapted to be engaged by a removal means so that said module can be readily removed from said rolling mill.

I UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,786,66L Dated Januar 22, 1971+ Inventor(s) A. JOHGS, Gt 8.1-

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 22, machine should read mill Column h, line 2, "device" should read drive Column 6, line 33, "whpn" should read when l Signed and sealed this lhth day of May lQTL (SEAL)- Attest: EDWARD M.FLETCHER,JR. C. MARSHALL DANN Atte sting Officer 7 Commissioner of Patents FORM powso uscoMM-oc scan-Poo GOVERNMENT PRENTING OFFICE "I! 0-888-38. 

1. A rolling mill module for a rolling mill for rolling a billet, said module having: a. a frame; b. a first pair of rolls journalled in said frame; c. a second pair of rolls journalled in said frame and spaced a predetermined distance from said first pair of rolls when the first pair of rolls and the second pair of rolls are in the rolling position so that the temperature drop in said billet between said first pair of rolls and said second pair of rolls is minimized; d. said module being adapted to be readily removed from said rolling mill; and e. wherein one pair of rolls of said first pair of rolls and said second pair of rolls has:
 1. a first roll journalled in said frame;
 2. a second roll journalled in said frame and disposed adjacent said first roll;
 3. a first fluid operating means connected to one roll of said first roll and said second roll;
 4. a second fluid operating means connected to the other roll of said first roll and said second roll;
 5. said first fluid operating means being adapted to provide greater fluid pressure on said one roll than said second fluid operating means applies to said other roll; and
 6. spacing means carried by one roll of said first roll and said second roll so that when said first fluid operating means reaches the end of its stroke, said spacing means limits the operating stroke of said second fluid operating means thereby providing a predetermined rolling spacing between said first roll and said second roll as said first roll and said second roll move from an open position to a rolling position.
 2. a second roll journalled in said frame and disposed adjacent said first roll;
 2. The rolling mill module recited in claim 1 and having: a. a first roll mounting means for mounting said first roll and adapted to be engaged by said first fluid operating means; and b. a second roll mounting means for mounting said second roll and adapted to be engaged by said second fluid mounting means.
 3. a first fluid operating means connected to one roll of said first roll and said second roll;
 3. The rolling mill module recited in claim 1 and having roll retracting means associated with one roll of said first roll and said second roll and adapted to engage the other roll of said first roll and said second roll so that when the fluid pressure is removed from said first fluid operating means and said second fluid operating means, said roll retracting means returns said first roll and said second roll to the open position.
 4. The rolling mill module recited in claim 1 and having a pressure release means associated with said first fluid operating means and said second fluid operating means, said pressure release means being operable when the pressure between said first roll and said second roll exceeds a predetermined pressure to release the fluid pressure on said first fluid operating means and said second fluid operating means thereby preventing damage to said first roll and said second roll from cast cold head ends, cold tail ends or the like and automatically releasing said first roll and said second roll from said rolling position.
 4. a second fluid operating means connected to the other roll of said first roll and said second roll;
 5. said first fluid operating means being adapted to provide greater fluid pressure on said one roll than said second fluid operating means applies to said other roll; and
 5. The rolling mill module recited in claim 3 and having a pressure release means associated with said first fluid operating means and said second fluid operating means, saiD pressure release means being operable when the pressure between said first roll and said second roll exceeds a predetermined pressure to release the fluid pressure on said first fluid operating means and said second fluid operating means thereby preventing damage to said first roll and said second roll from cast cold head ends, cold tail ends or the like and automatically permitting said roll retracting means to return said first roll and said second roll from said rolling position to said open position.
 6. The rolling mill module recited in claim 1 wherein said first pair of rolls are horizontal rolls.
 6. spacing means carried by one roll of said first roll and said second roll so that when said first fluid operating means reaches the end of its stroke, said spacing means limits the operating stroke of said second fluid operating means thereby providing a predetermined rolling spacing between said first roll and said second roll as said first roll and said second roll move from an open position to a rolling position.
 7. The rolling mill module recited in claim 1 wherein said first pair of rolls are vertical rolls.
 8. The rolling mill module recited in claim 1 wherein said first pair of rolls are angularly disposed with respect to a vertical axis of said module.
 9. The rolling mill module recited in claim 1 wherein said second pair of rolls are horizontal rolls.
 10. The rolling mill module recited in claim 1 wherein said second pair of rolls are vertical rolls.
 11. The rolling mill module recited in claim 1 wherein said second pair of rolls are angularly disposed with respect to said module.
 12. The rolling mill module recited in claim 1 and having: a. a first drive means connected to said first pair of rolls for rotating said first pair of rolls; and b. a second drive means connected to said second pair of rolls for rotating said second pair of rolls.
 13. The rolling mill module recited in claim 1 wherein said predetermined distance between the roll centers of said first pair of rolls and said second pair of rolls is less than the maximum roll diameter of said first pair of rolls and said second pair of rolls plus about four inches.
 14. The rolling mill module recited in claim 1 and having engaging means adapted to be engaged by a removal means so that said module can be readily removed from said rolling mill.
 15. A rolling mill module for a rolling mill for rolling a billet, said module having: a. a frame; b. a first pair of rolls journalled in said frame; c. a second pair of rolls journalled in said frame and spaced a predetermined distance from said first pair of rolls when the first pair of rolls and the second pair of rolls are in the rolling position so that the temperature drop in said billet between said first pair of rolls and said second pair of rolls is minimized; and d. wherein said predetermined distance between the roll centers of said first pair of rolls and said second pair of rolls is less than the maximum roll diameter of said first pair of rolls and said second pair of rolls plus about four inches.
 16. The rolling mill module recited in claim 15 wherein said first pair of rolls are horizontal rolls.
 17. The rolling mill module recited in claim 15 wherein said first pair of rolls are vertical rolls.
 18. The rolling mill module recited in claim 15 wherein said first pair of rolls are angularly disposed with respect to a vertical axis of said module.
 19. The rolling mill module recited in claim 15 wherein said second pair of rolls are horizontal rolls.
 20. The rolling mill module recited in claim 15 wherein said second pair of rolls are vertical rolls.
 21. The rolling mill module recited in claim 15 wherein said second pair of rolls are angularly disposed with respect to said module.
 22. The rolling mill module recited in claim 15 and having: a. a first drive means connected to said first pair of rolls for rotating said first pair of rolls; and b. a second drive means connected to said second pair of rolls for rotating said second pair of rolls.
 23. The rolling mill module recited in claim 15 and having engaging means adapted to be engaged by a removal means so that said module can be readily removed from said rolling mill. 